Who was the creator of rubber?

Use of nested switch case? What component makes up the high side of an AC system? Is it possible to have more than one public class in the same file? Which is better wet steam or dry steam? What are some of the benefits of a digital electricity meter? What electric motor is designed to turn into electrical energy into? How do you push and pop stack elements? What is the DC volts? What did Sir Rowland Hill invent? What is the meaning of standard ton of refrigeration? What is advantage of shunt trip of over uvt coil? What is the function of an expansion tank and compression tank? What is programming backlog? Can a vasectomy reverse itself after 20years? Who said it's the plumber? Is Lake Causeway the longest bridge in the world? How do you write script G? Which activity is performed using static analysis tools? What does the word essayons mean referring to US armyy engineers? What are importance of air to the technology?